This proposal seeks support for a methodological investigation of the role of randomized, controlled, clinical trials (RCTs) in the assessment of health care technologies. RCTs are rarely conducted and, when available, are often subject to a variety of methodological problems. As a consequence, it is typical to find new medical technologies being widely diffused as a result of weak evidence derived from uncontrolled studies involving a few patients. The objective of the research proposed in this application is to improve the quality of technological assessment by targeting evaluations to those innovations likely to be diffused and by developing methods to improve the evidence available in assessing the safety and efficacy. Our assumption is that given the tension between regulation and the desire to facilitate innovation, little increase in the rate of RCTs for technology assessment will be achieved. Instead, three strategies and for improveing these assessments are proposed: (a) identifying and selecting likely innovations for assessment, (b) secondary analysis RCTs to remove flaws in the design and analysis, and (c) meta-analysis of the non-randomized evaluatives studies to determine their bias in estimating efficacy and safety. A literature review of major medical journals for the period 1960-1970 is proposed to identify both successful and unsuccessful technologies. A secondary analysis of saphenous-vein coronary artery bypass graft surgery is proposed to investigate the methodological problems posed by lack of patient adherence to assigned therapy. Meta-analyses of coronary bypass and electronic fetal monitoring are also proposed to assess the utility of the quasi-experimental studies in evaluating medical innovations. Our focus is on life-preserving or life-sustaining technologies and on preventing the rapid diffusion of Type I medical innovations--those of little value or narrow application.